A person support apparatus may, among other things, support a person in a laying-down or a seated position. One or more sensors, which may be operably coupled to the person support apparatus, monitor changes in the position of a person situated on the person support apparatus. A control system receives output from the sensor or sensors over a period of time, while the person is positioned on the person support apparatus. The control system makes a determination relating to the activity and/or mobility of the person positioned on the person support apparatus. The control system may use the activity and/or mobility determination to control a feature of the person support apparatus, or for other purposes.
